Whilst I am far from being a Jet fan (no surprises there) this is one area in which one can't really blame them (dammit!).

Consideration of pregnancy, amongst other things, unfortunately, is a matter of goodwill of an individual rather than regulation. It's just Russian Roulette that this happened on Jet; it could (and does) just have easily have happened on any other airline, no matter how good or bad.

The EU compensation is a whole different matter. And that too is something all airlines go to great lengths to avoid paying. You just have to demand it, if you are eligible.